Technical Abstract:
Introduction
Colostrum provides immunoglobulins (Ig) and nutrients essential for calf health and performance. However, colostrum may be a source of exposure to significant pathogens including Mycobacterium avium subsp. paratuberculosis. Pilot studies have suggested that heat-treatment of colostrum may offer two potential benefits to the calf; reduced pathogen exposure and improved passive absorption of colostral Ig. 1 The objective of this study was to describe the effects of on-farm heat-treatment of colostrum on colostrum characteristics and calf health and performance.
Materials and Methods:
Newborn calves were enrolled from six commercial dairy farms in MN and WI during the summer of 2007. First milking colostrum was collected from fresh cows and refrigerated. Refrigerated colostrum was pooled, daily or on alternate days, to create unique batches of colostrum. One half of each unique batch was kept raw while the second half was heat-treated at 60oC for 60 minutes using a commercial on farm batch pasteurizer. Calves did not suckle, but were alternately assigned untreated or heat-treated colostrum and fed 3.8L within two hours of birth. Samples of fresh and heat-treated colostrum were frozen for culture and IgG testing. Serum was collected from calves between 1-8 days of age to determine IgG levels. Three farms recorded birth and weaning weights. Treatment and death events until weaning were recorded on all farms.
Results:
Treatment did not significantly affect colostrums IgG levels but significantly reduced colostral microbial counts. Calves fed heat-treated colostrum had significantly improved serum IgG levels (16.97 mg/ml) versus calves fed fresh colostrum (14.48 mg/ml). There was no effect of treatment on average daily gain (kg/day) or risks for treatment or mortality in the first 60 days of life. Study animals will be followed into adulthood to describe the treatment effect on longevity, milk production and risk for subclinical infection with Mycobacterium avium subsp. paratuberculosis.
Reference:
Johnson, J., S. Godden, T. Molitor, T. Ames, and D. Hagman. 2007. The effect of feeding heat treated colostrum on passive transfer of immune and nutritional parameters in dairy calves. J. Dairy Sci. 90: 5189-5198.
Acknowledgements:
This project was funded by USDA-CSREES.